Telephone system



Dec. 15, 1925- H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 Sheets-Shet 1 Dec. 15, 1925 1,565,269

- H. M. FRIENDLY TELEPHONE SYSTEM FiledMarch 30. 1922 16 Sheets-Sheet 2 Invaniuw Dec. 15 1925- H. M. FRIENDLY TELEPHONE SYSTEM J 1 E I 5 m m A m v mzm W m m I .D m H s 6 H Y 1 QR M w 9% o 3 RR h C m M .Qm \QQ d m WW. W F

m w wwm *Q NMN 16 Sheets-Sheet 4 Invenhnr I Herhefl-P'I-Friendlg W7 H. M.'FRlENDi,.Y

TELEPHONE SYSTEM Filed March 30. 1922 Dec. 15, 1925 H. M. FRIENDLY TELEPHONE SYSTEM Dec; 15. 1925- Filedv March 30, 1922 16 Sheets-Sh t 5 Invenrur HErhEFT-P'I-FriEndlg Dec. 15, 1925-] I H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30, 1922 16 Sheets-Sheet 6 Dec. 15, 1925. H. M. FRIENDLY TELEPHONE SYS TEM 16 Sheets-Sht '7 Filed March 30, 1922 Inveniur Herb erl'lTFriendl Po NmN 3h H. M. FRIENDLY TELEPHONE SYSTEM Dec. 15, 1925. 1,565,269

Filed March 30. 1922 16 Sheets-Shet a N w 0 03 3? 8 B Invanlur- Hrherilq-Friendlg Dec. 15, 1925 H. M. FRIENDi.Y

TELEPHONE SYSTEM Filed March 30, 1922 16 Sheets-Sht 9 Dec. 15, 1925' H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 Sheets-Sheet 10 WNW mwb

mud

Inveninr- H EPh erl-IT-Friendlg M AM Dec. 15, 1925- H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 Sheets-Sht ll We M EL I Dec. 15, 1925' H. M. FRIENDLY TELEPHONE SYSTEM Fi..ed March 30, 1922 16 Sheets-Sheet 12 Rh W i NHJ Dec. 15, 1925- 1,565,

H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 ShGBtS-Sht 15 Invaniur- Herherfl l-Frlendlg Wrm a m Dec. H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 Sheets-Sheet 14 N q. a 0) 0 D Q w *3 g Q 8 El E1:

Inv B11101"- Herherr-PI-Friendly Dec. 15, 1925- 1,565,269 H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 16 Sheets-She't 15 w v V 0 0 E? WVM 16 Sheets-Sheet l6 Invahtur- Herh erfITFr'xendlg H. M. FRIENDLY TELEPHONE SYSTEM Filed March 30. 1922 Dec. 15 1925 Patented Dec- 15, 192s. I p

*UNITED'STATES PATENT OFFICE.

HERBERT H. FRIENDLY, OF PORTLAN D, OREGON.

TELEPHONE SYSTEM.

Application filed larch 80, 1922. Serial No. 548,165.

I To all whom it may concern:

Beit known that I, HERBERT M. FRIENDL a citizen of the United States, residing at Portland, in the county of Multnomah and State of Oregon, have invented a certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

The present invention relates to telephone systems in which selector switches, are employed. More specifically, the invention relates to an improved method and apparatus whereby certain mechanism of selectors is dispensed wlth, and apparatus units in volving essentially the displaced mechanism provided. The apparatus units are arranged so that the are normally operatively related to a plura ity of selectors,.which it will appear, need not belong to the same numerical order. The latter is to say, that an apparatus unit may serve a plurality of selectors,

. which may be a mixture of first, second and certain control elements, elimination of third selectors, for example.

In incorporating-the present invention, I

provide apparatus units in smaller number,

one-thirtieth as many, for example, as there are selectors. Due to the common relation of thus efi'ecting the such control elements from each selector, a considerable saving in first cost and containing s ace is effected.

In designing and 'uilding automatic or machine switching telephonic apparatus, for example, the totalfirst cost is often a factor which will preclude its commercial adaptability. That is to say, apparatus,

which may be operatively successful, due to its cost'may not be commercially admissible. The latter may refer to a comparison of costs with other methods of interconnecting, as b manual methods, for example. To this en it is necessary to build apparatus of the general class to which the present invention relates, within a cost limit, rather than wholly to functional and service results. The

latter, will mean that relays, for example,

must be built, whichwill not exceed certain costs, even though service efliciency may be sacrificed thereby, as compared to ible efiiciency. Itisoften determined t at the inefiiciency which may accrue because of sacrificing efficiency and reliableness to the ends of reducing costs will be off-set by thenecessary, those employed may be made having higher tractive torque, thus permitting stifier and wider margins of adjustments, with attending advantages by way of more reliability. The present invention involving a common set of control relays serving a plurality of selectors, asagainst a specific set of control relays for each selector, entails a saving in first cost which may be applied to improve the quality and reliableness of the single control relay set employed. This will insure greater reliableness to the cooperative selectors and further the localization of such defectivenessas may occur from time to time.

Where a selector having a specific set of control relays becomes inoperative, the maintenance employee must assume the defectiveness of it may be caused from a defective condition in any of the component elements of the selector. Where vital elements involved in the functioning of a selector are commonly cooperative with other selectors, as in the present invention, and but a single one of the said cooperative selectors manifests inoperativeness, it may be generally assumed that the cause is resident in elements specific to the selector concerned. The arrangement as contemplated in the present invention thus circumscribes the seat of the defectiveness, and therefore, conducesto its more ready location.

The present invention also contemplates a possible, and moreover, this is not unusual in commercial systems. WVhere this occurs in intermediate links, as by a. selector being seized by two antecedent selectors, or by line switches, for example, there will be no listening-in on a completed connection possible, because the further progress of the call cannot take place. At least, where such an intruding condition occurs, it creates a. very undesirable impression in the minds of the users, and may lead to complaint which will require investigation at cost to the operating concern.

In obviating the last foregoing possibility 'I provide a common conductor for each selector. This conductor leads through a marginal relay in the apparatus unit to ground. Taps are made from the common conductor to a bank contact companion to. the private and line bank contacts of the leading-in terminals corresponding to the selectors, the taps being made through a set of normally closed contacts on the switching relay of the respective selector. The line re lay of the line switch is arranged to be connected to an auxiliary wiper, for example, when the switching relay operates, so the line relay, which has its live terminal connected to grounded battery, is then connected to the said common conductor. The marginal relay will be thus energized, but not to a degree sufiiciently to operate it. However, should two line switches be in seized relation to a selector, due to the selector being seized coincidentally, the concerned apparatus unit will. have two line switches related to it and consequently will have two line relays thereof in parallel energizing the marginal relay in the apparatus unit. Under the latter said condition the said marginal relay will be operatively energized. The release trunk from the. apparatus unit. loops through a set 'of'normally closed contacts on the said marginal relay, and this release trunk applies a ground overa common conductor, and through a second set of normally closed contacts on the switching relay of each selector to the conductor leadmg to the corresponding bank contact engaged by the respective private wipers of accessible line switches, to maintain the line switch seized in the mannerwell known in the art. It will be thus manifest that where two line switches seize a selector, the said marginal relay of the apparatus unit will open the release trunkand cause the line switches to unseize to cause them to again hunt. The ground winding of the line relay of the apparatus unit carries a tone, audible to a calling party which has attained connection with a selector and associated appa ratus unit. When the tone is perceived the calling party will know that the circuits are in readiness to receive directive impulses.- In the case of the line switches becoming un- 05 seized,'as last referred to, wherein they will institute a re-hunting operation,the tone will cease and be again reapplied upon a selector being again seized. The tone application being very brief will not be noticed, in view of the fact the said marginal relay disconnects the tone when it operates. In'this connection, it Will be noted that the line relay of the line switch will be maintained energized (though not necessarily operatively), until after the selector cuts-in, whereby the apparatus unit is operatively disconnected therefrom.

" It will appear that an apparatus unit is only exclusively converted to the use of a selector upon the concerned selector becoming seized by-an antecedent switch, and that it will be disconnected therefrom upon the said concerned selector cutting-in, to be again reassociated, subject to directive control, upon the concerned selector unseizing and. restoring. It will thus appear that the apparatus unit is in exclusive control of a selector only for the period from the time the selector is seized, and until the selector seizes, which period will usually not be over two seconds; in fact, in many instances this time will be less than a second, the time, of course, depending upon the promptness of sending the directive impulses after the selector is seized, and upon the number of impulses in the digit series sent. In view of the fact the av rage time of holding a connection is eighty seconds in" some exchanges, it will appear that the apparatus unit may in due course serve to control a large number of selectors within the average time a selector is held.

There being one apparatus unit for thirty selectors, for example, and the fact that all idle embracedselectors thereof are'barred when the apparatus unit is converted, it will appear that if. a line becomes electrically closed, due to a trouble condition wherein the line switch will seize a selector, it will mean that all idle selectors of the group containing it will be barred against seizure, as if they were all busy. T0 guard against such contingency, the apparatus units are arranged with a time element relay which serves to. automatically control the seized selector so that it will rotate over all the bank contacts of the first level and operate an off-normal spring vsetby way of releasing the apparatus unit and applying a tone upon the calling line. It will also cause a lamp to glow as a signal to the attendant of the condition. The selector will be restored when the condition of the line becomes normal. Only one of the apparatus units shown incorporates I the .last referred-to The same plan in disclosing has ampled system, it being considered evident how specifically applied devices may be generally applied.

Referring to the drawings Fig. ;1 is an apparatus unit A incorporating a time element device for disassociating 1t from a seized selector.

Fig. 2 shows a first'selector FS and re- Selector FS is cooperative with FS and A".

Fig. 8 is an apparatusunitA Fig. 9 shows a first selector FS and relate circuits. Selector FS is cooperative with A and SS.

Fig. 10 shows two connectors C and C having access to substations T and T. The said connectors are reached through selectors SS6, SS and SS, and'other selectors of the respective groups containing said latter selectors.

\ Fig. 11 shows a substation T leading to a line switch L. The line switch L is'one of a group having access to selector FS and other selectors of the group containing the latter said selector.

Fig. 12 shows a substation T leading to a line switch L The line switch L is one of a group having access to selector FS", and other selectors of the group containing the latter said selector.

Fig. 13 shows two su'bstations. T and T leading to line switches L I and II, respectively. The latter, said line switches (and other line switches of the group containingl them), have access to selector FS?-,

the latter sa'idselector.

Fig. 14 shows connecting lines o1n1ng' and other selectors of the group containing Figs. 9 and 15.

Fig. 15 shows Figs. 7 and 10. "a

Fig. 16 is a diagrammatic layout of the equipment elements shownin Figs. 1 to 13,-

inclusive.

Fig. 17 shows the assembly of the figures to organize a system shown diagrammatically in Fig. 16,'being the system chosen to elucidate the invention. Lines extending to the margins of the sheets Whichregister with lines extending to the ,margins of adjacent sheets are to be understood as being the same line, respectlvely.

connecting 'lines' joining Line switches L ,.L", L and L are of the general class, and in fact may be assumed as of the exact type as the telephone designated A in U. S. re-issued to Frank Newforth, .April 13th, 1915.-

Line switches L L, L and L are of the general class as shown in U. S. Patent N 0. 1,193,160, granted to Lamb, August, 1st,

1916.. The line switches L and L 'are modified, however, to operate in accordance with the present invention. Line switches L and L are well known in the art.

The selectors shown, when cooperated with their respectively embracing apparatus unit Patent No. 13,901

son and Erickson, No. 815,321, granted March. 13th, v mechanical and circuit details to operate on the well known so-called two wire principle, and in accordance with the present inven-'- tion.

sumed as of the exact type as connector H of The connectors C and C may be asi comprise complete selectols of the general class shown in U. S. patent to Keith, Erick- 1906, of course, modified in v the said'citedpatent to Newforth.

By referring to Fig. 16, it" will be observed that there are three groups of line.

switches, B,'C and D, each group having access to a first selector, though it will be understood that a plurality of first selectors, not shown, are, in each;instance, accessible Line switches will not ordinarily have access .to more than one selector embraced by an apparatus unit, though due to the fact that while selectors may have corresponding bank- I n 0 positions In the various line switches accessible thereto, the bank contact sets accessible to the line switches will not be tested for in the same order, due to the fact that the line switches have no'normal resting. position.

More than one selector embraced by an apparatus "unit may, in fact, be accessible" to a line switch or line switches. In the case of selectors, it is preferred to have but one selector of a group embraced by an appaj 'ratus unit accessible to any selector, so that as a selector rotates over busy bank contacts testing for an idle selector, each set of bank contacts so tested will refer to a selectorembraced by a different apparatus unitthan before tested. That is to say, if there are.

ten sets of bank contacts, referring to ten v selectors, there will be ten apparatus units respective to the said selectors concerned.

Under the condition, if an apparatus unit embraces thirty selectors, each one of the latter said selectors will be accessible, to one of thirty groups of selectors, "for example. It will also appear that the selectors embraced by an apparatus unit may refer to different numerical orders, so 'the said thirty groups of selectors may refer to a mixture of numerical orders and also of groups thereof, as has been referred to in a general way hereinbeforev When a selector encounters a set of bank contacts as busy, the condition may be due to the correspondingselector being operatively busy in a connection, or that the apparatus unit embracing the selector tested may be busy by one of its embraced selectors having been seized and the apparatus unit is still converted due to the said selector not having cut-in, it being remembered that when a selector is seized, all idle selectors embraced by its apparatus unit will be barred against seizure, by the apparatus unit. In view of the fore-v going, should there be first, second and third selectors an apparatus'unit may embrace a selector of each of ten groups of first, second and third selectors. Where the connections to the selectors are lapped, as is a-comnion practice, .the groupings will ordinarily,

though not necessarily, contemplate that a level of a selector will not refer to more than vone selector embraced by any apparatus unit.

In order to make the full disclosure as brief as possible, all figures will not be de scribed in detail specifically, where similar figures have been so described. That is,

where there are line switches, selectors and apparatus units having relays and equipment elements correspondingly drawn, they are to be' assumed as having the same adjustments and corresponding functions as similarly drawn and disposed ones described. To aid in identifying the various similar elements, the numerical designations thereof l will have an indexdigit corresponding to the figure concerned where three digits comprise the designation, the last two digits corresponding to the last two figures of designations where detailed description has been made. With reference to letter designations, an exponent digit corresponding to the figure concerned serves to corelate the element with a similar element referred to in a description employingthe same letter with an exponent to correspond to the concerned figure under description.

It will be assumed that a call is initiated at substation T and that the call is to be extended to substation T the telephone number of which is 1112. A circuit can be traced from the winding of slow-releasing line relay B armature 51, receiver of substation T armature 52 to grounded resting contact, the relay B actuating. Assuming that private bank contact 54 of the set 53 to 55 (inclusive) constitutes ground, a circuit can be traced from the ground on wiper 58,

' 0f the set 57 to 59, armatures 60 and 61, conductor 62 to the winding of motor magnet ,M- the latter said magnet attracting its armature by .way of interrupting the last traced energizing path, and upon the retraction of the said armature consequent thereto the set of wipers 57 p to 59 will be driven into engagement with bank contact set 63 to 65 (respectively), the described operation of the magnet M re-occurring if wiper 58 encounters ground on bank contact 64. However, it will be assumed that the bank contact 64 doesnot constitute ground, and therefore no ground will have been applied to conductor 62. In this connection it will be noted that the upper armature of relay B grounds the upper winding terminal of' relay C, while the lower winding terminal of vthe said relay is attached to the conductor 62, while wiper 58 rested on bank contact 54, assumed to be grounded, so relay 0 is not energized under the condition. However, if no ground is'applied to conductor 62, by reason of wiper 58 not receiving a short-circuit to ground through bank contact 64, the m0- tor magnet M and the relay C -will become energized in series to the upper armature of relay B, the relay C actuating, the motor magnet M not being operatively energized due to the resistance of the winding of relay C, When the armature 60 attracts, ground on the upper armature of relay B is applied through the armature 60, wiper 58 to bank contact 64 and connections. Attention is particularly directed to the fact that at the tim. ground was assumed maintained on conductor 62, from Wiper 58, battery is being derived from the motor magnet and applied through the said wiper 58 to thebaiik contact engaged by it, but under the assumed condition of the bank contact 54 constituting ground potential the conductor 62 will correspondingly constitute ground potential. It follows, that if there is an ohmic resistance value, such as is involved in the lower winding of slightly slow-releasing relay B for example, which isconnected from ground to bank contact 64 and its multiples accessible to other line switches of the group containing L over conductor 201,

the conductor 62 will not then constitute ground, though its potential will be high enough to not operatively energize the motor magnet M The resistance value of the lower winding of relay B is high enough to not short-circuit the winding of relay 9 below its operative value, though a high enough to restrict the current so as to not operatively energize the motor magnet M -So' it will be clear that 'at the time relay C energizes and operates when wiper 58 en gages bank contact 64, the lower winding of relay B will be energized. The ad ustment of relay B is'such that it will operate under the latter condition, though only its armature 202 need be operated at this juncture.

Due to the attracted condition of the upper armature of relay B and armature 60, the battery potential initially applied through the lower winding of relay B will be changed to ground potential. However, since relay B has attracted its armature 202 coincident with the attraction of armature 

